Around two-thirds of it sank off the coast of Japan, but the rest is now drifting across the Pacific towards North America, stretching across an estimated 6300 kilometres of ocean. Much of it will swirl around for ever in the fabled garbage patch in the north Pacific.
The problem with the Great Pacific Garbage Patch is that it's hard to spot. Most of it consists of tiny bits of plastic, forming a thin and constantly shifting film on the surface of the ocean. Garbage patchologists say it's twice the size of Texas, and has been likened to ''a big toilet that never flushes''. 
Indeed, there is little indigenous pollution, yet smaller islands and reefs of Hawaii for example, are littered with fishing lines, bottle tops, Lego pieces, golf tees, plastic bottles, toothbrushes, cigarette lighters, syringes, tyres, petrol cans and plastic dinosaurs, swept there by the currents of the north Pacific subtropical gyre. 

The patch formed due to oceanic gyres—rotating systems of ocean currents that have a whirlpool-like effect on debris. In the center, there is very little current, leaving all the plastic stuck in one giant spot. Similar garbage patches have formed in the Atlantic Ocean and in the Southern Hemisphere, although the Pacific Ocean patch is believed to be the largest and most-studied.
Experts disagree on where most of the plastic comes from—some have estimated that 80 percent of it comes from land sources, others say more of it is from shipping junk—but they agree there's little the public can currently do about it. While plastic breaks down into smaller pieces, it never fully decomposes, so what's left behind in the ocean is there indefinitely. At the moment it is simply not cost-effective to skim the surface of the ocean to remove this garbage.

No one can blame the Japanese for the latest surge of garbage, however, for the great tide of crap that is flooding the Pacific, the rest of us will have to carry the can.